title: Characterisation of micro-sized and nano-sized tungsten oxide-epoxy composites for radiation shielding of diagnostic X-rays.
abstract: Characteristics of X-ray transmissions were investigated for epoxy composites filled with 2-10 vol% WO3 loadings using synchrotron X-ray absorption spectroscopy (XAS) at 10-40 keV. The results obtained were used to determine the equivalent X-ray energies for the operating X-ray tube voltages of mammography and radiology machines. The results confirmed the superior attenuation ability of nano-sized WO3-epoxy composites in the energy range of 10-25 keV when compared to their micro-sized counterparts. However, at higher synchrotron radiation energies (i.e., 30-40 keV), the X-ray transmission characteristics were similar with no apparent size effect for both nano-sized and micro-sized WO3-epoxy composites. The equivalent X-ray energies for the operating X-ray tube voltages of the mammography unit (25-49 kV) were in the range of 15-25 keV. Similarly, for a radiology unit operating at 40-60 kV, the equivalent energy range was 25-40 keV, and for operating voltages greater than 60 kV (i.e., 70-100 kV), the equivalent energy was in excess of 40 keV. The mechanical properties of epoxy composites increased initially with an increase in the filler loading but a further increase in the WO3 loading resulted in deterioration of flexural strength, modulus and hardness.
authors.affiliation: Department of Imaging and Applied Physics, Curtin University, GPO Box U1987, Perth, WA 6845 Australia; School of Physics, Universiti Sains Malaysia, 11800 Penang, Malaysia.
authors.forename: N Z Noor
authors.initials: NZ
authors.lastname: Azman
authors.forename: S A
authors.initials: SA
authors.lastname: Siddiqui
authors.forename: I M
authors.initials: IM
authors.lastname: Low
mesh_terms: D004852:Epoxy Compounds / Q000737:chemistry*; D006244:Hardness; D010087:Oxides / Q000737:chemistry*; D010316:Particle Size; D011835:Radiation Protection / Q000295:instrumentation*; D014414:Tungsten / Q000737:chemistry*; D014965:X-Rays
chemical_list: D004852:Epoxy Compounds; D010087:Oxides; C511604:tungsten oxide; D014414:Tungsten
keywords: Filler loading; Micro-sized WO(3)-epoxy composites; Nano-sized WO(3)-epoxy composites; X-ray shielding; X-ray transmission